Posts Tagged ‘logical fallacies’

Have you ever been arguing with someone and you felt that there was something wrong with her argument, but you couldn’t figure out what it was? Perhaps she was utilizing some form of logical fallacy. A fallacy is an unsound argument based on faulty reasoning. Logicians have identified scores of fallacies.

Here are some examples of common logical fallicies:

Appeal to fear

“Are you sure you want to give me a ticket, officer? I play golf with the chief of police.”

Things could get pretty ugly around here if I don’t get what I want.

Appeal to pity
You should go out with me because forty-three women have already turned me down and I can’t take much more rejection.

Circular Reasoning (A=B because B=A)

Lebron James is the greatest basketball player of his generation because nobody else is as good as he is.

My mom is terrific because she is wonderful.

Appeal to Common Practice

It’s no big deal to leave trash on the ground in a parking lot. A lot of people do it.

But Mom, all the other parents let their kids stay out until dawn, so you should too.

Post hoc (causal) fallacy

When the rooster crows, the sun rises. Therefore, the rooster causes the sun to rise.

The Lakers won last night because I wore my lucky sweater.

False Dilemma (or False Alternatives)

It will either be hot or cold tomorrow.

You must be a Lakers fan or a Clippers fan.

Slippery Slope

If we allow gay marriage, people will start marrying their dogs.

If we ban Hummers because they are bad for the environment, eventually the government will ban all cars.

Non Sequitur (“It does not follow”)

That man is an awful person because he is wearing a blue sweater.

I cannot eat a cupcake because it is Tuesday.

Loaded question

Have you stopped wetting your bed yet?

Do you still have a Spongebob lunch pail?

Distinction without a Difference

I’m against capital punishment, but I believe we should execute serial killers.

I don’t have a sweet tooth; I just love to eat candy.

One of the most common fallacies is ad hominem, which means attacking a person instead of addressing her arguments.

Here are two examples of irrelevant ad hominem argument which have nothing to do with the legitimacy of a person’s arguments:

1)

Dave: I think the death penalty is a good idea.Larry: Who cares what you think? You are a stupid, pathetic loser and your mother dresses you funny.

2)

I’m not going to listen to any of your arguments because you wear Member’s Only jackets and you sleep with a Teddy Bear.

An Ad hominem argument is a great way to avoid the merits of another person’s arguments? Many English teachers say that it is never appropriate to engage in ad hominem arguments. But is it legitimate to attack a person for being hypocritical? My answer is: Sometimes.

Here is an example of a situation where an ad hominem argument is clearly inappropriate:

Let’s say my doctor tells me after a checkup that my blood pressure is too high and I need to lose weight and I should quit drinking and smoking. I respond: “What are you talking about, Dude? I see you drinking and smoking at my bar every night and you are seriously overweight.

My ad hominem is illegitimate in this case because my doctor is giving me medically viable advice even though he doesn’t practice what he preaches. He went to medical school and he knows what he’s talking about.

Here is an example of a situation where an ad hominem argument is appropriate:

Speaking of practicing what we preach, what about someone like megachurch preacher Ted Haggard who righteously espouses clean living and family values—until he gets caught in a hotel room with a male masseur and a bunch of meth? Does Haggard’s behavior render his message any less legitimate? Yes, because he is bolstering his argument by holding himself up of as a paragon of someone who is living a righteous lifestyle.

A tautology is a grammatical construct; circular reasoning is a logical fallacy. The two phenomena are related but not identical.

A tautology is a sentence in which the conclusion is equivalent to its premise. In other words, in a tautology, the predicate can be surmised by reading the subject.

Here are some examples of tautologies:
My mother’s brother is my uncle.

Father Brown is a priest.

It is what it is.

A circular argument occurs when someone affirms her position simply by restating it in different terms. In other words, circular reasoning is an argument where the conclusion depends upon or is equivalent to its premise.

In a circular argument:

X is true because of Y.

and

Y is true because of X.

A circular argument is similar in structure to a tautology, but a circular argument includes causal reasoning (because, therefore, for this reason, etc.).

Here are some examples of circular reasoning:

My mom is terrific because she is wonderful.

People do what Dave tells; therefore, he is a great leader.

I slumbered beyond my assigned wakeup time; that’s why I overslept.

Lesson Evaluation: Explain why the following examples are tautologies, circular arguments, or neither.